1. Field
One or more embodiments described herein relate to a display device.
2. Description of the Related Art
A display may be classified as a passive matrix display or an active matrix display according to its driving method. An active matrix display is suitable for large-area displays because it consumes less power and has higher resolution than a passive matrix display. Also, an active matrix display includes a pixel driving circuit connected to a liquid crystal capacitor or a light-emitting diode.
Examples of these displays include liquid crystal displays, electrophoretic displays, organic light-emitting displays, inorganic electroluminescent displays, field emission displays, surface-conduction electron-emitter displays, plasma displays, and cathode ray tube displays.
Organic light-emitting displays display images, characters, and other information based on pixels that emit light based on a combination of holes and electrons in an organic layer. In operation, the intensity of current flowing through an electroluminescent (EL) element of each pixel may change over time, thereby causing a display non-uniformity. This is because the current flowing through the EL element may change because of a change in the threshold voltage of the driving transistor.
The threshold voltage of a driving transistor may change, for example, based on various manufacturing process variables. Therefore, it may be difficult to manufacture driving transistors having equal threshold voltages in an active matrix display. This will result in a threshold voltage difference among the pixels.